The US President has warned of "enormous consequences" if evidence emerges of chemical weapons being moved around or utilised in Syria.
Barack Obama has said that Washington is monitoring the situation in the country closely and while he has not ordered intervention "at this point", the US could still intervene in the country's civil war.
The US President said that if Syria looks like it might use its chemical weapons, it would be considered an act of aggression.
The comments came on the day that a female Japanese reporter was killed while covering clashes in the northern city of Aleppo.